Radioreceiver



O. C. DENNIS RADIO RECEIVER June 24, 1 939.

Filed Oct. 10. 1927 4 Sheets-Sheet H m p O/IUQPC ag- Lg? IIIHHIHHHHIHH IHIHII I June 24, 1930. o. c. DENNIS RADIO RECEIVER Filed Oct. 10. 1927 4 SheetsSheet 17111071 .07.- O/[l @7 01 Dani/2M9 G [Hill Ill June 24, 1930.

'0. C. DENNI$ RADIO RECEIVER Filed Oct. 10. 1927 4 Sheets-Sheet s 4 Sheets-Sheet 4 mokm mmm QEI o. c. DENNIS RADIO RECEIVER Filed Oct. 10. 1927 KKK June 24, 1930.

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Patented June 24, 1930 UNITED STATES OLIVER G. DENNIS, OF WILMETTE, ILLINOIS RADIORECEIVER Application'flled October 10, 1927. SeriaI'No. 225,213.

My invention relates to radio receivers andhas for its broad object the provision of a radio receiver of simplified and improved construction and performance.

Radio receiving sets wit-h single dial controlhave simplicity in' handling which has made them very popular with the ultimate purchaser. The usual method of tuning such sets is by means of variable condensers and most single dial sets have the condensers con-' nected in a single gan so that they will all be turned together, t ereby theoretically obtaining substantially the same capacity setting on each condenser. Considerable efficiency is lost in theseold arrangements however, as it is a practical impossibility to construct a plurality of condensers having balanced capacities at each setting.

There are other faults to be found with the usual resent day commercial sets including the di culty withwhich the parts are assem bled, the relatively high cost expended unnecessarily on unimportant details, the inexcessabiliy of the various parts for repair purposes and the like.

Among the specific objects of the present invention is the provision of an improved single dial control for a plurality of variable condensers.

Another object is to produce is single dial control which may be quickly converted into tube supporting means.

Another object is to provide an improved coil mounting. I

Another object is to provide an improved panel assembly.

Other objects will be apparent from a consideration of the following detailed description explaining the main features of the invention and accompanied by the drawings, wherein- Fig. 1 is a plan view of my improved receiver removed from its cabinet;

Fig. 2 is a fragmentary front elev'ational view thereof, showing the tuning arrangement on the front panel;

Fig. 3 is a sectional view taken along the I line 33 of Fig. 1 and showing the control dial in elevation;

Fig. 4 is an enlarged plan view of a portion of Fig. 1;

Fig. 5 is a fragmentary vertical section taken along the line 5-5 of Fig. 4;

Fig. 6 is an elevational view looking at the end of Fig. 4;

Fig. 7 is a section along the line 77 of Fig.4;

Fig. 8 is a iary panel; Fig. 9 shows the wiring diagram;

Fig. 10 is a detail of the tube socket; and

Fig. 11 is a fragmentary section showing the coil mounting.

Reference may now be had to the drawings wherein one embodiment of my invention is shown incorporating in a preferred form the features of the invention. The construction and arrangementof the various portions of the apparatus and the manner in which they are combined results in a receiver which ma be produced very economically but whic nevertheless surpasses in tone quality selecbottom plan view of the auxiltivity and all around performance, other reably secured to the metal panel 10 as by the immovable apparatus is so disposed on thepanel that all of the wiring is accomplished on the reverse or bottom side thereof, so that the upper partof the panel is free of any obstructions and presents a clean flat surface encumbered only by the apparatus.

The c'ircuitis so arranged that only a rela-- -tively small number of wires 1616 extend between the two panels. These are made easily detachable if desired so that the two panels-may be assembled separately during manufacture and then secured together by fastening thewires on condenser 16 in place. In the practical embodiment of these features, I have only six wires secured across between the two panels. I

The apparatus mounted on the front panel, comprises a plurality of variable condensers l717 provided with the usual rotor and stator plates and have their rotor plate'shafts 18-18 in alignment. As indicated, the condensers are arranged in pairs, two on each side of the panel, the rotor shaft being common to two condensers. The two rotor shafts have their contiguous ends almost abutting, and each-of these shafts is provided with a hand wheel 19 through the operation of whi h the rotor shaftsmaybe actuated to .vary the capacity of the condenser. Normally, the two hand wheels 19 would be operableseparately but a pin 21 is secured in suitably provided aperturesin the wheeIS to fasten them together so that-they and all of the condensers Wlll turn a single unitary system.

The condensers as previously observed are mounted in pairs, each pair having end plates 22 secured to the panel 10 and having the rotor shafts 18 journaled therein. Each end together as plate has suitably secured thereto, a tension.

spring 23.adapt ed to bear against a shoulder (Fig. 4) provided on the rotor shafts for the purpose of holding the shafts against possible end play and supplying the requisite tension thereto.

Secured between each'pair of end plates are three rectangular bars 24 to which the stator plates are adapted to be'scured. The

' securing or fastening means is so constructed that the stator platesmaybe moved with respect to the rectangular mounting bars for the purpose of adjusting the capacity of each individual condenser. s

Each set of stator plates26 has secured thereto, a plurality of spacers 27, the construction of these spacers being preferably as disclosed in my co-pending application Serial No. 756,391, filed December 17, 1924. The spacers project slightly below the outside edge of the group of stator plates and ends through which a machine screw 31 is 0 adapted to extend to secure the spring clip 29 against movement. The construction is the same for each one of the spacers 27, there being a spacer on each group of stator plates for each one ofthe bars 24.

This construction permits the stator plates to be adjusted with respect to the rotor plate so that the capacity of a condenser may be modified; It is apparent that any one of the spacers ,may be slightly moved without sub stantial change in the adjustmentof the other spacers and in this way the capacities of the various condensers may be madeto coincide for the same setting.

As the drawing indicates, two of the spacers are located within easy access, being above and below thecondenser'but the third spacer is positioned against the panel so that nor mally it would be impossible to loosen the screw 31 to permit adjustment of this portion of the condenser. -To obviate this difficulty however,'a screw driver. hole-32 is provided in the steelpancl but not the face panel, so that during assembly and test of the receiver technicians may be able to make all of the adjustments required; but after the receiver is completedthis hole. is covered up so that it will not be within easy reach of. the ordinary user.

Referring again to the hand wheels, each is provided with a graduated paper tape secured thereon by suitably provided screws 34 and having giaduations in kilocycles, meters or any arbitrary arrangement of numbers which might be desired. Each hand wheel is provided with a pair of stops 36-436 adapted to strike the panel and prevent complete rotation of the condensers. These stops are so arranged that they serve as a support for the tapes, as such tapes may be hooked under the stops while they are being placed on the face of the wheels and before the screws 34 are screwed into position. Since one stop strikes the upper part of the panel to limit the turning and the other strikes the lower part, it is apparent that the pin 21 will never be within reach from the front of the panel tubes and the like, the 2 in one feature may have some advantage when tuning in on a distant stationwhere the signals are somewhat weak. i

Any suitable system of current control may be employed with the present receiver but good results have been obtained by the use of the rheostat. The circuit is arranged so that a single rheostat will control the current input to the radio frequency and detector tu e while the fixed resistance is provided for the audio tube. The rheostat is mounted on the front panel so the rheostat knob37 is positioned near the bottom of the escutcheon plate and immediately below the condenser control.

Attention may now be directed to the rear. or auxiliar panel to which the immovable portions 0 the apparatus are secured. In Fig. 1 the top of the auxiliary panel is shown and is illustrated with coils 4l41 secured on the upper face thereof with suitable tubes 42. nd a grid leak 43 resiliently held between sui able terminals. Binding posts 44 at the left of the panel provide means for connecting the receiver into the operating electrical circuit, some of the wires so secured to these posts being adapted to extend to a source of current, the other bindingposts leading to the aerial and ground wires.

Instead of employing the conventional type of tube socket, a novel arrangement is provided whereby the auxiliary panel itself serves as a portion of the socket and a better result is obtained than by the use of the usual sockets, the contacts and all the wires incidental thereto, being .kept below the panel. In the provision of this arrangement, a number of holes are formed in the panel, one for receiving each one of the terminal lugs 46 at the base of the tube. ,This is a total of four holes for each tube and they are arranged in clusters of four in convenient places on the panel so as to obtain the spacing arrangement shown. Immediately ad 'acent to each hole is a terminal contact 47 0 spring material se cured by a rivet 48 to the underside of the panel. Each one of these terminal contacts is provided with a portion 48 adapted to closely abut the contact lug on the radio tube when the lug is extended through the hole in the panel andv has an angularly disposed projection 48* to which a wire conductor forming a part of the circuit is soldered.

The coils 41 are also secured to the panel throu h a novel arrangement which produces a muc better and more economical structure than any heretofore known. The coils have a hollow insulating core 51 to the upper part of which is secured a secondary winding .52' while a primary winding 53 is coiled around the bottom of the core' in alignment with the secondary winding. Near the base of the hollow core, terminals 54 are secured by means of rivets 56, these terminals being four in number and connected to the ends of the coils. Four holes through the panel are adapted to receive the terminals which project to the underside of the panels through these holes and are bent over in the manner illustrated in Fig. 11, to secure the coil in an immovable position on the panel. The bent-over ends of the terminals serve as connections to which proper wire conductors forming a part of the circuit are soldered. In this way it will be observed that the same terminal strip serves three functions, namely as a terminal for the coils, as a securing means for fastening the coil core to the panel and as a terminal for interconnecting the conductor and the coils.

Fig.9 showsa circuit which isparticularly ond audio a CX112 or equal.

With this hook up embodied in a receiver having the features described and shown, I

am able to get exceptional selectivity with the unit control balanced coils. and paired.

condensers and without employing the 2 in one feature, which however may improve reception at certain times, as for instance when tuning in a distant station;

What I claim as new and desire to secure by United States Letters Patent is as follows:

1. In a radio receiver, a front panel, a pair of variable condensers secured on the reverse side of said panel and having their rotor plate -shafts in alignment, a pair of hand w eels each se'curedto one of said shafts and positioned side by side with a portionof their arcs extending through the panel for turning the same, and a quickly removable pin extending through the two hand wheels causing them normally to be operated in unison but adapted to be removed to permit independent adjustment.

2. A radio receiver as defined inclaim 1, with a pair of stops carried by the wheels, said removable pin being between the stops so that'the back of thepanel will have to'be exposed in order to remove'the pin.

3. A radio receiver as defined in claim 1, with a pair of stops carried by the hand wheels, said wheels also adapted to have indicator tapes and said tapes guided into position by said stops.

4. In a radio receiver, a plurality of con-' densers with their rotor plate shafts in alignment and connected for turning by a single ing members secured to the spacers and threaded on the bars, a spring clip ada ted to engage each .pair of mounting mem rs to secure them in immovable position on the barsand fastening means extending throu h the clip and engaging the bar for securingt e clip to the bar, an elongated slot being provided in the clip to permit movement t ereof longitudinally of the bar so that the stator d plates may be adjusted sidewise.

5. In a radio receiver a plurality of condensers with their rotor plate shafts in ali ment, a plurality of bars for supporting t e stator plates thereon, a plurality of eon-4 15 nections from the stator plates to the bars adapted tobe slidable thereon, spring clips for engaging the connections to. secure them in immovable positions on the bars, fastening means extending through the clips and 20 secured to the barsfor securing the clips thereto, an elongated slot being provided ln the clips to permitmovement thereof longitudinally of the bars, a plurality of hand Wheels one on each rotor shaft contiguously g5 placed and having aligned apertures therein, and a. removable pin for engagement in the the apertures to lock the hand wheels together for unit operation of the condensers. In witness whereof, I hereunto subscribe 30 my name this 2nd day of September, 1927.

OLIVER C. DENNIS. 

